Electrosurgical stapling apparatus

ABSTRACT

An electrosurgical stapling apparatus is provided which uses thermogenic energy as well as surgical fasteners or staples for strengthening tissue, providing hemostasis, tissue joining or welding. The thermogenic energy also strengthens tissue in proximity to a staple line and knife cut line and provides hemostasis along the staple and cut lines formed by the staples and a knife blade during surgical stapling. The use of thermogenic energy provides short-term hemostasis and sealing, and reduces or prevents staple line and cut line bleeding, while the stapling features provide short and long-term tissue strength and hemostasis. The stapling apparatus further substantially reduces or prevents knife cut line bleeding by energizing a knife blade for cauterizing tissue while it is being cut. In one embodiment, energy is applied to the anvil to energize the staples as they make contact with the anvil.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application No. 11/707,818filed Feb. 16, 2007, now U.S. Pat. No. 7,559,453, which is acontinuation of U.S. application No. 10/513,435 filed Nov. 1, 2004, nowU.S. Pat. No. 7,207,471, which claims priority under 35 U.S.C. 371 fromInternational application No. PCT/US2003/014520 filed May 9, 2003, whichclaims benefit of U.S. Provisional application No. 60/379,961 filed May10, 2002. The disclosures of each of the above-identified applicationsare hereby incorporated by reference in their entirety.

FIELD OF THE INVENTION

This invention relates to surgical staplers, and more particularly, toan electrosurgical stapling apparatus for sequentially applying aplurality of surgical fasteners to body tissue.

BACKGROUND OF THE INVENTION

Surgical procedures requiring cutting of tissue can result in bleedingat the site of the cutting. Various techniques have been adapted tocontrol bleeding with varying degrees of success such as, for example,suturing, applying clips to blood vessels, and using surgical fasteners,as well as electrocautery and other tissue heating techniques.

Surgical devices using surgical fasteners entail grasping or clampingtissue between opposing jaw structure and then joining the tissue byemploying the surgical fasteners. These devices are well known in theart. In some instruments a knife is provided to cut the tissue which hasbeen joined by the fasteners. The fasteners are typically in the form ofsurgical staples however, two part polymeric fasteners are alsoutilized.

Instruments for this purpose can comprise two elongated members whichare respectively used to capture or clamp tissue. Typically, one of themembers carries a cartridge which houses a plurality of staples arrangedin at least two lateral rows while the other member comprises an anvilwhich defines a surface for forming the staple legs as the fasteners aredriven from the cartridge. Where two part fasteners are used, thismember carries the mating part, e.g. the receiver, to the fastenersdriven from the cartridge. Generally, the stapling operation is effectedby a pusher which travels longitudinally through the cartridge carryingmember, with the pusher acting upon the staples to sequentially ejectthem from the cartridge. A knife may travel with the pusher between thestaple rows to longitudinally cut and/or open the stapled tissue betweenthe rows of staples. Such instruments are disclosed in U.S. Pat. Nos.3,079,606 and 3,490,675.

A later stapler disclosed in U.S. Pat. No. 3,499,591 applies a doublerow of staples on each side of the incision. This is accomplished byproviding a cartridge assembly in which a cam member moves through anelongate guide path between two sets of staggered staple carryinggrooves. Staple drive members are located within the grooves and arepositioned in such a manner so as to be contacted by the longitudinallymoving cam to effect ejection of the staples. Other examples of staplersare disclosed in U.S. Pat. Nos. 4,429,695, 5,065,929, and 5,156,614.

Electrocautery devices are preferred in certain surgical procedures foreffecting improved hemostasis by heating tissue and blood vessels usingthermogenic energy, preferably radiofrequency energy, to causecoagulation or cauterization. Monopolar devices utilize one electrodeassociated with a cutting or cauterizing instrument and a remote returnelectrode, usually adhered externally to the patient. Bipolarinstruments utilize two electrodes and the cauterizing current isgenerally limited to tissue between the two electrodes of a tissuetreating portion (e.g., end effector) of an instrument.

It would be desirable to have electrosurgical stapling devices combiningthe structural and functional aspects of stapling instruments andelectrocautery devices to provide improved hemostasis by usingthermogenic energy to cause coagulation or cauterization and surgicalfasteners to staple the tissue, either before, during or after the useof thermogenic energy.

Therefore, it is an aspect of the invention to provide anelectrosurgical stapling apparatus which uses thermogenic energy andstaples for providing hemostasis, tissue joining or welding, and alsostrengthens tissue in proximity to a staple line and provides hemostasisalong the staple line to reduce or prevent staple line bleeding.

SUMMARY

An electrosurgical stapling apparatus is disclosed which usesthermogenic energy, preferably radiofrequency energy, as well assurgical fasteners or staples for strengthening tissue, providinghemostasis, tissue joining or welding. The thermogenic energy alsostrengthens tissue in proximity to a staple line and knife cut line andprovides hemostasis along the staple and cut lines formed by the staplesand a knife blade during surgical stapling. The use of thermogenicenergy provides short-term hemostasis and sealing, and reduces orprevents staple line and cut line bleeding, while the stapling featuresprovide short and long-term tissue strength and hemostasis.

Staple line bleeding is reduced or prevented by the apparatus bythermogenically energizing the staples before, during, and/or after astapling procedure to increase the temperature of the staples to atemperature sufficient to cauterize tissue. Hence, as the staplespenetrate the tissue, the tissue is cauterized, thereby reducing orpreventing staple line bleeding.

Since staple line bleeding is reduced or prevented, the apparatus of thepresent invention makes it possible to extend the applicable range ofspecific staple sizes to include thinner, thicker and highlyvascularized tissue. Accordingly, large-size staples can be used, forexample, with the apparatus of the present invention to join thin,highly vascularized tissue.

One embodiment of the apparatus is an improved surgical staplerincluding a first body portion defining a surface against which aplurality of surgical staples are driven when ejected from a second bodyportion by an actuation member, which can be a sled, mounted totranslate through the first body portion. The second body portion housesthe plurality of surgical staples. The improved surgical stapler furtherincludes at least one conductive member supported by the first bodyportion for sequentially applying thermogenic energy to the plurality ofsurgical staples for providing hemostasis along at least one staple lineduring surgical stapling.

The type of thermogenic energy applied to the surgical staples can beradiofrequency, pure thermal, or resistive heating. The at least oneconductive member can be a metallic anvil, where the surface is an outersurface of the metallic anvil. The surface includes a plurality ofstaple-receiving recesses and preferably is coated with an insulationmaterial. The insulation material can be configured for being partiallyremovable by staples when driven against the first body portion duringsurgical stapling for energizing the surgical staples via the at leastone conductive member. Alternatively, the plurality of staple-receivingrecesses are not coated with the insulation material. The insulationmaterial can be selected from the group consisting of Teflon andplastics.

The actuation member or sled can include a knife blade that can besupported by or fastened to an upstanding flange. The knife blade cantraverse through a knife slot, cavity, track, etc. formed in the firstbody portion. At least one other conductive member can be used to applythermogenic energy to the knife blade during surgical stapling tocauterize tissue along at least one cut line. The at least one otherconductive member can be a surface which defines the knife slot, cavity,track, etc. formed in the first body portion. The at least oneconductive member energizes the plurality of surgical staples via thesurface defined by the first body portion for providing hemostasis alongat least one staple line during surgical stapling.

Another embodiment of the apparatus includes a first body portionsupporting a metallic anvil plate which defines a fastener formingsurface and a second body portion configured to releasably mate with thefirst body portion. In the detailed description which follows, the firstand second body portions of the apparatus are also referred to as the“anvil half-section” and “cartridge half-section”, respectively.

The second body portion can include a disposable loading unit, andeither can include a cartridge defining a plurality of slots and atissue contacting surface, a plurality of surgical fasteners disposed inthe slots of the cartridge, and a plurality of ejectors or pusherspositioned adjacent the surgical fasteners. The surgical fasteners andthe ejectors preferably are fabricated from a metallic alloy or othertype of material capable of carrying thermogenic energy.

A metallic actuator or actuation sled can be provided in the disposableloading unit is positioned and configured to enter and translate throughthe cartridge to sequentially interact with the pushers. The actuator isenergized or electrified by radiofrequency energy generated by anexternal radiofrequency generator or other thermogenic generator forenergizing the surgical fasteners via the pushers. The externalgenerator is connected to the actuator or actuation sled via at leastone wire for energizing the actuator upon activation of the externalgenerator.

The apparatus further includes an elongated actuation member mounted forlongitudinal movement within the second body portion or cartridge andreleasably engagable with the actuator or actuation sled, wherebylongitudinal movement of the actuation member causes the actuator tointeract with the ejectors, driving the surgical fasteners from thecartridge to be formed against the anvil plate.

The first body portion preferably includes an elongate anvil supportmember and a pivoting lever handle. The anvil plate is preferably formedseparate from the anvil support member and includes a plurality ofstaple forming pockets defining the anvil forming surface. The anvilplate also includes means for engaging the anvil support member duringassembly of the apparatus to securely fasten the anvil plate to thesupport member. The anvil plate is connected via at least one returnwire to the external generator to behave as a return electrode withrespect to the actuator of the disposable loading unit and the surgicalfasteners for bipolar operation.

A notched area is defined adjacent a proximal end of the anvil supportmember and correspondingly positioned detents are formed adjacent aproximal end of the second body portion. The notched area and thedetents cooperate to facilitate relative pivotal movement of the firstand second body portions when they are mated with one another.

Preferably, a pair of upstanding flanges are formed on the disposableloading unit proximal of the tissue contacting surface thereof. Theflanges define a structural tissue stop to limit the movement of bodytissue. The flanges are also dimensioned to engage a pair ofcorresponding apertures formed in the anvil plate to maintain the firstand second body portions in alignment with one another when theapparatus is in a closed or clamped position.

The actuator of the disposable loading unit is preferably monolithicallyformed from a planar piece of sheet metal during a stamping process andincludes a planar base and a pair of upstanding parallel cam wedges. Anupturned flange is formed at a distal end of the actuation member forreleasably engaging a complementary slot formed in the base of theactuator. The actuator preferably further includes an upstanding supportflange to which a knife blade is fastened. The knife blade is providedto form an incision in the stapled body tissue while also beingenergized by thermogenic energy via the actuator for improvedhemostasis. It is contemplated to connect the knife blade to theactuator via a non-conductive member, e.g., a plastic member, if heatingof the knife blade is not desired, or to simply remove the knife bladefrom the upstanding support.

A retaining channel depends from a distal end of the second body portionfor supporting the disposable loading unit. Preferably, the disposableloading unit and the retaining channel include complementary engagementstructures for releasably securing the disposable loading unit in theretaining channel. Opposed bearing structures are formed in theretaining channel at a proximal end thereof for abutting the anvilsupport beam when body tissue is clamped between the anvil plate and thetissue contacting surface of the cartridge. The bearing structures serveto inhibit the anvil support beam from bending as a result of thecompressive forces generated during clamping.

The thermogenic energy can be monopolar or bipolar radiofrequency, purethermal, and resistive heating, and is applied to the stapling apparatusto energize or heat the staples either directly and/or via one or moreconductive members before, during, and/or after the apparatus hasstapled, cauterized, and/or cut tissue.

Still, another embodiment of the invention includes a surgical staplerincluding a first body portion supporting an anvil which defines afastener forming surface; a second body portion configured to releasablymate with the first body portion; and an elongated actuation membermounted for longitudinal movement within a cartridge, which can be adisposable loading unit, supported by the second body portion. Theelongated actuation member has an engagement member releasably coupledto engagement structure to enable pushing and pulling of the actuationmember to effect movement of the actuation member in proximal and distaldirections, respectively. The surgical stapler further includes at leastone conductive member for applying thermogenic energy to the surgicalfasteners via the engagement member for providing hemostasis along atleast one staple line during surgical stapling.

The cartridge defines a plurality of slots and a tissue contactingsurface; a plurality of surgical fasteners disposed in the slots of thecartridge; a plurality of ejectors positioned adjacent the surgicalfasteners; and an actuator configured to translate through the cartridgeto sequentially interact with the ejectors. The type of thermogenicenergy applied to the surgical fasteners can be selected radiofrequency,pure thermal, or resistive heating.

The first body portion can include an elongate anvil support member anda pivoting lever handle for approximating the first and second bodyportions. At least one return wire can be connected to the elongateanvil support member for bipolar operation with respect to the at leastone conductive member. The anvil can include an anvil plate formedseparate from the first body portion and includes a plurality of stapleforming pockets. The first body portion has an anvil support member andthe anvil plate includes structure for engaging the anvil support memberduring assembly of the surgical stapler to securely fasten the anvilplate to the anvil support member. A notched area can be definedadjacent a proximal end of the anvil support member and correspondinglypositioned detents can be formed adjacent a proximal end of the secondbody portion. The notched area and the detents cooperate to facilitaterelative pivotal movement of the first and second body portions.

A pair of upstanding flanges can be formed on the disposable loadingunit proximal of a tissue contacting surface thereof. The pair ofupstanding flanges are dimensioned to engage a pair of correspondingapertures formed in the anvil plate to maintain the first and secondbody portions in alignment with the surgical stapler in a closedposition.

The actuator can include a planar base portion and/or a pair ofupstanding parallel cam wedges. An upturned flange is formed at a distalend of the actuation member for releasably engaging a complementary slotformed in the base portion of the actuator. The actuator can bemonolithically formed.

The surgical stapler can include a knife blade, and the at least oneconductive member further applies thermogenic energy to the knife bladeduring surgical stapling. The knife blade can be carried by the actuatorand the at least one conductive member can further apply thermogenicenergy to the knife blade during surgical stapling.

A retaining channel can depend from a distal end of the second bodyportion for supporting the disposable loading unit. The retainingchannel can include engagement structure for releasably securing thedisposable loading unit in the retaining channel. Opposed bearingstructures can be formed in the retaining channel adjacent a proximalend thereof for abutting the anvil support beam when body tissue isclamped between the anvil plate and the tissue contacting surface of thecartridge.

The surgical stapler can include a firing knob extending from the secondbody portion for sliding movement in a longitudinal direction. Theelongated actuation member can be operatively connected at a proximalend to the firing knob. The staple actuator can include a planar baseportion, a pair of upstanding parallel cam wedges disposed in astaggered orientation and an upstanding blade support flange to which aknife blade is fastened. The staple actuator can include an upturnedflange formed at a distal end of the elongated actuator for releasablyengaging a complementary slot formed in the base portion of the stapleactuator.

Still in another embodiment, a surgical stapler for applying a pluralityof surgical fasteners to body tissue is provided. The surgical staplerincludes a first body portion having an anvil which defines a fastenerforming surface against which surgical fasteners are driven; a secondbody portion having an elongate retention channel; and a cartridgeand/or a disposable loading unit supported in the elongate retentionchannel of the second body portion. The cartridge defines a plurality ofslots and a tissue contacting surface; a plurality of surgical fastenersdisposed in the slots of the cartridge; a plurality of ejectorspositioned adjacent the surgical fasteners; and an actuator configuredto enter and translate through the cartridge to sequentially interactwith the ejectors. The surgical stapler further includes at least oneconductive member supported by the second body portion for applyingthermogenic energy to the plurality of surgical fasteners forstrengthening tissue in proximity to at least one staple line and/or forproviding hemostasis along the at least one staple line during surgicalstapling.

The type of thermogenic energy applied to the surgical fasteners can beradiofrequency, pure thermal, or resistive heating. The actuator caninclude two upstanding cam wedges, an upstanding flange positionedbetween the cam wedges, and a knife blade attached to the upstandingflange. The surgical stapler can include an elongated actuation membermounted for longitudinal movement within the second body portion andoperatively associated with the actuator such that longitudinal movementof the actuation member causes the actuator to interact with theejectors to drive the surgical fasteners from the cartridge to be formedagainst the anvil.

In the alternative, the surgical fasteners are energized via the anvil.In this embodiment, the anvil surface is energized which in turnenergizes the surgical staples as they contact the anvil surface duringsurgical stapling. It is preferred to coat the metallic anvil surfacewith an insulating material, such as Teflon, soft plastics (PVC), etc.,to prevent the energized anvil surface from energizing tissue which iscontacted by the anvil surface.

During a surgical stapling procedure, as the staples are ejected againstthe anvil surface, the staples scratch off the insulation coating andmake contact with the metallic anvil surface, thus becoming energized.In the alternative, the staple-forming pockets of the anvil surface arenot coated, such that the staples do not need to scratch off theinsulation coating. The rest of the anvil surface, however, isinsulated. Further, it is preferred for the anvil to energize the knifeblade as the knife blade traverses through the disposable loading unitby making contact with the knife blade, either directly or indirectly.

A method is further disclosed for providing hemostasis along at leastone staple line during surgical stapling. The method includes the stepsof providing a plurality of surgical fasteners; and applying thermogenicenergy to an anvil surface against which the plurality of surgicalfasteners are driven when ejected by a staple actuator for energizingthe plurality of surgical fasteners via the anvil surface. The methodcan further comprise the step of applying thermogenic energy to a knifeblade during surgical stapling, either via the anvil surface and/or someother structure, such as a cartridge housing the plurality of surgicalfasteners. The thermogenic energy can be applied to the surgicalfasteners via the anvil surface sequentially, and the type ofthermogenic energy applied to the surgical fasteners via the anvilsurface can be radiofrequency, pure thermal, or resistive heating. Asdiscussed above, the entire anvil surface or the entire anvil surface,except for the pockets configured to engage the surgical fasteners, ispreferably insulated to prevent the anvil surface from energizingtissue.

During surgical stapling, the surgical fasteners are ejected and scratchthe material insulating the anvil surface (if the pockets are coated),thereby becoming energized. If the pockets are not coated, the surgicalfasteners make contact with the metallic anvil surface and becomeenergized.

Further features of the surgical apparatus of the invention will becomemore readily apparent to those skilled in the art from the followingdetailed description of the apparatus taken in conjunction with thedrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the surgical stapling apparatus of the inventionwill be described hereinbelow with reference to the drawings wherein:

FIG. 1A is a perspective view of an electrosurgical stapling apparatusconstructed in accordance with a preferred embodiment with the clampinghandle thereof disposed in an upright open position;

FIG. 1B is a perspective view of the electrosurgical stapling apparatusillustrated in FIG. 1A with the clamping handle disposed in a closedposition;

FIG. 2 is an exploded perspective view of the electrosurgical staplingapparatus of FIGS. 1A and 1B;

FIG. 3 is a perspective view of the lower body portion of theelectrosurgical stapling apparatus of FIGS. 1A and 1B;

FIG. 4A is a top plan view of the retention channel of theelectrosurgical stapling apparatus of FIGS. 1A and 1B;

FIG. 4B is a side elevational view of the retention channel shown inFIG. 4A;

FIG. 4C is a perspective view of the retention channel of FIGS. 4A and4B with the disposable loading unit retained therein;

FIG. 5A is an enlarged perspective view, with parts separated for easeof illustration, of the disposable loading unit and actuation assemblyof the electrosurgical stapling apparatus of the subject application;

FIG. 5B is a cross-sectional view showing the engagement of thecartridge lip and the retention channel;

FIG. 6A is a perspective view of the actuation sled of the disposableloading unit shown in FIG. 5A in a pre-formed condition;

FIG. 6B is a perspective view of the actuation sled shown in FIG. 6A ina formed condition with the knife blade separated therefrom forillustrative purposes;

FIG. 6C is a perspective view of the formed actuation sled shown in FIG.6B with the knife blade mounted to the blade support portion thereof;

FIG. 7 is a plan view of the preformed anvil plate which is mounted tothe anvil support beam of the upper body portion of the electrosurgicalstapling apparatus shown in FIGS. 1A and 1B;

FIG. 7A is a plan view of the preformed anvil plate which is mounted tothe anvil support beam of the upper body portion of the electrosurgicalstapling apparatus shown in FIGS. 1A and 1B having an insulationmaterial applied thereon;

FIG. 8 is a cross-sectional view of the preformed anvil plate takenalong line 8-8 of FIG. 7;

FIG. 8A is a cross-sectional view of the preformed anvil plate takenalong line 8-8 of FIG. 7A;

FIG. 9 is a front end view of the preformed anvil plate illustrated inFIGS. 7 and 8;

FIG. 9A is a front end view of the preformed anvil plate illustrated inFIGS. 7 and 8 having an insulation material applied thereon;

FIG. 9B is a front end view of the preformed anvil plate illustrated inFIGS. 7 and 8 having an insulation material applied thereon;

FIG. 9C is a top view of the preformed anvil plate illustrated in FIGS.7A and 8A having an insulation material applied thereon except withinstaple-forming cups;

FIG. 9D is a cross-sectional view of a portion of the preformed anvilplate illustrated in FIGS. 7A and 8A having an insulation materialapplied thereon and within staple-forming cups;

FIG. 10 is a perspective view of the upper body portion of theelectrosurgical stapling apparatus of FIGS. 1A and 1B with an enlargedlocalized view of a distal portion thereof illustrating the connectiveengagement between the anvil plate and the anvil support beam;

FIG. 11 is an exploded perspective view of an embodiment utilizing alockout mechanism to prevent reactuation of the apparatus;

FIG. 11A is an enlarged cross-sectional view of the T-shaped member ofthe lockout mechanism;

FIG. 12 is an enlarged perspective view of the actuation channel havingan edge for engagement by the hook of the lockout mechanism;

FIGS. 13A and 13B are side views of the lockout mechanism illustratingits movement from a non-engaged to an engaged position;

FIG. 14 is a side elevational view in cross-section of theelectrosurgical stapling apparatus of the present invention with theactuation sled disposed in a pre-actuated proximal position;

FIG. 15 is a side elevational view in cross-section of theelectrosurgical stapling apparatus of the present invention with theactuation sled disposed in a partially advanced position;

FIG. 16 is a side elevational view in cross-section of theelectrosurgical stapling apparatus of the subject application with theactuation sled advanced to the distal end of the cartridge at theconclusion of a staple firing procedure;

FIG. 17 is a perspective view of an electrosurgical stapling apparatusconstructed in accordance with another preferred embodiment;

FIG. 18 is a perspective view of the distal end of the embodiment of thedisclosure shown in FIG. 17 with the cartridge assembly in an advancedposition;

FIG. 19 is an exploded perspective view of the device shown in FIG. 17;

FIG. 20 is a perspective view of an electrosurgical stapling apparatusconstructed in accordance with another preferred embodiment; and

FIG. 21 is an enlarged perspective view of an end effector of the deviceshown in FIG. 20.

DETAILED DESCRIPTION OF EMBODIMENTS

The present invention provides a stapling apparatus which usesthermogenic energy, preferably radiofrequency energy generated by anexternal radiofrequency generator, as well as surgical fasteners orstaples for strengthening tissue, providing hemostasis, tissue joiningor welding. The thermogenic energy also strengthens tissue in proximityto a staple line and knife cut line and provides hemostasis along thestaple and cut lines formed by the staples and a knife blade duringsurgical stapling. The use of thermogenic energy provides short-termhemostasis and sealing, and reduces or prevents staple line and cut linebleeding, while the stapling features provide short and long-term tissuestrength and hemostasis.

Staple line bleeding is reduced or prevented by the apparatus, bythermogenically energizing the staples before, during, and/or after astapling procedure to increase the temperature of the staples to atemperature sufficient to cauterize tissue. Hence, as the staplespenetrate the tissue, the staples cauterize the tissue, including bloodvessels, to reduce or prevent staple line bleeding.

Since staple line bleeding is reduced or prevented, the apparatus of thepresent invention makes it possible to extend the applicable range ofspecific staple sizes to include thinner, thicker and highlyvascularized tissue. Accordingly, large-size staples can be used, forexample, with the apparatus of the present invention to join thin,highly vascularized tissue. It is also provided that the presentinvention further reduces or prevents knife cut line bleeding byenergizing a knife blade for cauterizing the tissue while it is beingcut.

In the drawings and in the following description, the term “proximal”,as is traditional, will refer to the end of the apparatus which iscloser to the operator, while the term “distal” will refer to the end ofthe apparatus which is further from the operator.

Referring now to the drawings wherein like reference numerals identifysimilar structural elements, there is illustrated in FIGS. 1A and 1B anelectrosurgical stapling apparatus constructed in accordance with apreferred embodiment and designated generally by reference numeral 10which includes a cartridge half-section 11 a and an anvil half-section11 b. As will become readily apparent to those having ordinary skill inthe art, stapling apparatus 10 is constructed in such a manner so as tosubstantially reduce the costs associated with its fabrication andassembly as compared to prior art linear staplers.

Referring to FIGS. 2 and 3, stapling apparatus 10 includes a bodyportion 12 defining a handle for grasping and supporting the device. Aretaining channel 14 is mounted in the interior cavity 15 of bodyportion 12 adjacent the distal end thereof. Retaining channel 14 isdimensioned and configured to support a disposable loading unit 20, asillustrated in FIG. 4C.

As shown in FIG. 5A, the disposable loading unit 20 includes a cartridge22 having a plurality of slots 22 c which support a corresponding numberof metallic surgical staples 24, a plurality of metallic staple pushersor ejectors 26 adapted and configured to eject the staples 24 from slots22 c when acted upon by a staple driving force, and an actuation sled oractuator 28 which is mounted to translate through cartridge 22 in alongitudinal direction to transmit a staple driving force to ejectors 26while simultaneously energizing ejectors 26 by thermogenic energygenerated by an external generator, preferably a radiofrequencygenerator. The cartridge 22 is preferably composed of liquid crystalpolymer material; although other materials are contemplated. Thecartridge 22 has a lip 23 which engages the retention channel 14 toprevent inward rotation of the cartridge (see FIG. 5B).

As best seen in FIG. 6A, actuation sled 28 is preferably monolithicallyformed from a single piece of sheet metal or a similar conductivematerial which is folded into the desired structural configuration shownin FIG. 6C. In this configuration, actuation sled 28 defines a baseportion 30, two upstanding cam wedges 32 and 34, and an upstanding shank35 which supports a knife blade 36. Knife blade 36 is preferably spotwelded to shank 35, although other known fastening methods may beemployed, for transferring thermogenic energy to knife blade 36 viaactuation sled 28. It is contemplated to connect knife blade 36 toactuation sled 28 via a non-conductive member, e.g., a plastic member,if heating of knife blade 36 is not desired, or to simply remove knifeblade 36 from upstanding shank 35.

As illustrated in FIG. 6B, a weldment port 37 and a winglet 39 areprovided to facilitate the proper alignment and cohesion of knife blade36 to shank 35 during fabrication. Cam wedges 32 and 34 are staggeredwith respect to one another so that one leads the other throughout thesled's translation through cartridge 22. In doing so, the staple drivingforces within cartridge 22 remain balanced during a staple drivingoperation. Longitudinal slots 22 a and 22 b accommodate the longitudinaltranslation of cam wedges 32 and 34, while slot 22 c accommodates thelongitudinal translation of shank 35 (see FIG. 5A). Although illustratedwith a knife, it is also contemplated that the apparatus can be providedwithout a knife blade to staple tissue without making an incision.

The base portion 30 of actuation sled 28 has a transverse slot 40defined therein which is dimensioned and configured to releasably retainan upturned flange 42 formed at the distal end of elongated actuationchannel 44 (FIG. 5A). When the disposable loading unit 20 is placed intoretaining channel 14 and actuation sled 28 is disposed in itsproximal-most position, flange 42 releasably engages slot 40. Thus,movement of actuation channel 44 moves actuation sled 28.

As shown in FIG. 5A, at least one wire 47 is connected to actuationchannel 44 and to an external generator (not shown), preferably aradiofrequency generator, for providing thermogenic energy to actuationchannel 44 to energize or heat the same. The energizing of actuationchannel 44 causes the energizing of actuation sled 28 via upturnedflange 42, thereby also energizing cam wedges 32, 34. Cam wedges 32, 34in turn energize staple pushers 26 which in turn energize staples 24(see FIGS. 15 and 16). After a stapling operation, when disposableloading unit 20 is removed from the retaining channel, flange 42 iseasily disengaged from slot 40.

With continued reference to FIG. 5A, actuation channel 44 is defined bya base portion 45 and two parallel upstanding beams 46 and 48 ofelongate configuration. The distal ends of beams 46 and 48 are staggeredto match the staggered orientation of cam wedges 32 and 34,respectively. The proximal end of each beam projects rearwardly toengage a non-conductive mounting block 49 that is associated with firingknob 50. A pair of slots 52 (only one of which is shown) are formed inmounting block 49 for receiving the proximal end of each of theupstanding beams 46, 48 of actuation channel 44 and the slots areprovided with detents 54 for engaging apertures 56 in the beam ends tolockingly retain beams 46, 48 in mounting block 49. In use, longitudinalmovement of firing knob 50 causes corresponding longitudinal translationof actuation channel 44 and actuation sled 28.

Referring to FIGS. 2 and 4C, retention channel 14 includes a baseportion 60 and two upstanding parallel walls 62 and 64. Numericalindicia is imprinted on the walls 62, 64 of retention channel 14 toindicate the length of the staple line. Retention structures areprovided at the distal end of each of the walls 62, 64 to engagecorresponding structures provided on the disposable loading unit 20. Inparticular, notches 66 a and 66 b are provided for engagingcorresponding protuberances, such as protuberance 67, and slots 68 a and68 b are provided for engaging corresponding detents, such as detent 69.These structures inhibit lateral, longitudinal and perpendicularshifting of the cartridge 22 (and disposable loading unit 20) within theretaining channel 14. Ramped engagement slots 70 a and 70 b are alsodefined in the opposed walls of retention channel 14 for interactingwith a pair of opposed protuberances 72 a and 72 b (FIG. 5A) to guidethe disposable loading unit 20 into retention channel 14 when loadedinto the electrosurgical stapling apparatus 10.

Referring again to FIG. 2, the electrosurgical stapling apparatus 10further includes an elongate anvil support beam 80 which has a generallyU-shaped cross-sectional configuration. Anvil support beam 80 and itsassociated structures are all conductive, except where otherwise noted,and are also referred to herein as the “anvil half-section”. Distal endportion 88 of the anvil support beam 80 in one embodiment is tapered inheight “h” in a distal direction to provide additional support andreduce deflection during a staple firing operation. Proximal end portion82 of support beam 80 has a notched area 84 for engaging a pair ofcorresponding detents 86 (only one of which is shown), which extend intothe cavity 15 of body portion 12 adjacent the proximal end thereof.Detents 86 are engaged when cartridge half-section 11 a and anvilhalf-section 11 b are mated with one another. Distal end portion 88 ofanvil support beam 80 is configured to support a preformed anvil plate90 against which staples 24 are driven and formed during a staplingprocedure.

Referring to FIGS. 7 and 8, anvil plate 90 is formed from a unitarypiece of metal (conductive material) and is cold formed and stamped todefine a plurality of staple forming recesses, pockets or cups 91. Eachstaple forming recess corresponds to a particular staple housed withincartridge 22. Anvil plate 90, as shown in FIG. 2, is provided with twoopposed tangs 92 a and 92 b which extend inwardly to engagecomplementary engagement slots 93 b (only one is shown) in anvil supportbeam 80 during fabrication and assembly (see FIG. 10). Thecross-sectional configuration of anvil plate 90 is dimensioned tocomplement the cross-sectional geometry of support beam 80 (see FIG. 9).More particularly, cavity 97 which extends along the length of anvilplate 90 corresponds to a similar channel formed in support beam 80.These areas accommodate shank 35 and knife blade 36 as it translatesdistally to form an incision in stapled body tissue during a staplingoperation.

Surfaces 97 a of cavity 97, in one embodiment, can be energized forenergizing knife blade 36 as it translates distally abutting surfaces 97a of cavity 97. In another embodiment as shown by FIG. 9B, surfaces 97 aof cavity 97 are insulated by insulation material 89, such as Teflon,plastics (PVC), etc., to prevent an energized anvil plate 90 fromenergizing knife blade 36 or tissue within cavity 97.

A pair of rectangular apertures 95 a and 95 b are formed in anvil plate90 adjacent the proximal end thereof for receiving a pair ofcorrespondingly positioned flanges or projections 96 a and 96 b whichproject upwardly away from the tissue contacting surface (see FIGS. 2and 4C). The interaction between aperture 95 a, 95 b and flanges 96 a,96 b ensures that cartridge 22 and anvil plate 90 are properly alignedwith one another during a stapling procedure. Flanges 96 a, 96 b arespaced proximally of tissue stop portion 61 of retention channel 14.Portion 61 and the distal edge 13 of handle portion, best seen in FIG.3, cooperate to prevent tissue from extending proximally.

At least one return wire 81 is connected to anvil support beam 80 and tothe external generator for bipolar operation when the generator isactivated. Bipolar operation is achieved via wire 47, actuation channel44 and its associated structures, anvil plate 90 and its associatedstructures, anvil support beam 80, and wire 81. The non-conductivemounting block 49 as well as other non-conductive member or surfaces,such as the top surface of protective housing 25, insulates theconductive members of anvil half-section 11 b with the conductivemembers of cartridge half-section 11 a. It is contemplated that returnwire 81 can be removed for monopolar operation. It is furthercontemplated that other types of thermogenic energy can be appliedbesides radiofrequency energy, such as pure thermal and resistiveheating.

It is further contemplated to connect the at least one return wire 81 toa component other than anvil support beam 80, such as anvil half-section11 b, for energizing staples 24 via an anvil half-section structure,such as anvil plate 90. In this embodiment, anvil plate 90 is energizedwhich in turn energizes surgical staples 24 as they contact anvil plate90 during surgical stapling. It is preferred to coat metallic anvilplate 90 with an insulating material 89 (see FIGS. 7A-9B and FIG. 9D),such as Teflon, soft plastics (PVC), etc., to prevent the energizedanvil plate 90 from energizing tissue which is contacted by anvil plate90. FIG. 9D is an enlarged view of a portion of FIG. 8A showinginsulating material 89 coating staple-forming cups 91 of anvil plate 90.In FIGS. 7A-9C, the same reference numerals as in FIGS. 7-9 designatethe same or similar components.

During a surgical stapling procedure, as staples 24 are ejected againstanvil plate 90, staples 24 scratch off insulation coating or material 89and make contact with metallic anvil plate 90, thus becoming energized.In the alternative, staple-forming cups 91 of anvil plate 90 are notcoated (see FIG. 9C), such that staples 24 do not need to scratch offthe insulation coating or material 89. The rest of anvil plate 90,however, is insulated by coating it with insulating material 89.

Referring again to FIG. 2, anvil half-section 11 b of stapling apparatus10 further includes clamping handle 100 which is used to securely clamptissue between the staple forming surface of anvil plate 90 and thetissue contacting surface of cartridge 22. Clamping handle 100 ispivotably mounted to anvil support beam 80 about a transverse pivot pinwhich is not shown in the drawings. A pair of clamping hooks 102 a and102 b depend from clamping handle 100 for interacting with U-shapedclamping beam 104 supported within the internal cavity defined in handleportion 12.

When apparatus 10 is assembled prior to use, notched area 84 at proximalend 82 of anvil support beam 80 is engaged with the cooperating detents86 in the inner cavity 15 of body portion 12. Thereupon, anvilhalf-section 11 b is mated with cartridge half-section 11 a, andclamping handle 100 is disposed in the upright unclamped position shownin FIG. 1A.

Subsequently, when body tissue is properly disposed between the stapleforming surface of anvil plate 90 and the tissue contacting surface ofcartridge 22, anvil half-section 11 b is pivoted towards cartridgehalf-section 11 a, about the detents in body portion 12, such that thedistal ends of clamping hooks 102 a and 102 b are positioned immediatelyadjacent the proximal end of the base of U-shaped clamping beam 104.Concomitantly, flanges 96 a and 96 b engage apertures 95 a and 95 b inanvil plate 90 to ensure proper alignment of the anvil and thecartridge.

Then, to securely clamp the captured body tissue, clamping handle 100 ispivoted from the position illustrated in FIG. 1A to that which is shownin FIG. 1B. At such a time, clamping hooks 102 a and 102 b engage thebase of clamping beam 104, locking the apparatus in a clamped condition.During clamping, the captured body tissue exerts a counter-force againstthe tissue contacting surface of cartridge 22 and the fastener formingsurface of the anvil plate 90, urging the two structures apart. Toovercome these forces and prevent the proximal portion 82 of anvilsupport beam 80 from bending, bearing surfaces are defined withinretention channel 14 to support the compressive forces generated duringclamping. In particular, as illustrated in FIG. 4A, opposed bearingshelves 110 a and 110 b are stamp formed in opposed walls 62 and 64 ofretention channel 14. The bearing shelves are positioned to abut themedial section of anvil support beam 80 proximate the clamping handlepivot point.

It may also be desirable to provide a locking mechanism to preventreactuation of the apparatus after it has been actuated. For example, alocking member 120 shown in FIG. 11 can be positioned in the retainingchannel 114. Locking member 120 is biased to an upward engagementposition and each end extends through a window 141, 143 in the channel114. A T-shaped member 124 is positioned between the cam wedges 132, 134to bias the hook portion 122 out of engagement with the actuationchannel 144. Head portion 126 of T-shaped member 124 (FIG. 11A) isinitially retained in the cartridge by a pair of detents in thecartridge which extend into the knife slot. When the apparatus isactuated, head portion 126 of T-shaped member 124 is in the knife slot.

A second pair of detents (not shown) at the distal end of the knife slotengages head portion 126 of T-shaped member 124 to hold it at the distalend of cartridge 122 when cam wedges 132, 134 are advanced to the distalposition. When actuation channel 144 is retracted from the post-actuatedposition to the pre-actuated position, T-shaped member 124 remainsforward allowing hook portion 122 to return to the upward position andextend through the window 141 in retaining channel 114 to engage edge143 (see FIGS. 12 and 13A) of actuation channel 144 to preventadvancement of the actuation channel. FIGS. 13A, 13B illustrate movementof the locking member 120 from an initial non-engaged position (FIG.13A) out of engagement with actuation channel 144 to an engaged position(FIG. 13B) in engagement with actuation channel 144 to prevent distalmovement thereof.

Referring now to FIGS. 14-16, there is illustrated, in sequential order,a staple firing operation in which a plurality of staples are ejectedfrom cartridge 22 and driven against the staple forming surface of anvilplate 90. In operation, prior to firing electrosurgical staplingapparatus 10, actuation sled 28 is in the proximal-most position shownin FIG. 14. At such a time, knife blade 36 is enclosed in protectivehousing 25 formed adjacent the proximal end of disposable loading unit20. To fire the apparatus, firing knob 50 is moved in a distaldirection. Accordingly, as illustrated in FIG. 15, actuation channel 44drives actuation sled 28 distally into and through cartridge 22. Duringits distal translation, the angled leading surfaces of cam wedges 32 and34 sequentially contact ejectors 26, urging them in a directiontransverse to the direction of movement of actuation sled 28. As aresult, ejectors 26 push staples 24 from their individual slots, drivingeach staple into a respective staple forming cup 91 in anvil plate 90.

Sequential firing of the staples continues until actuation sled 28 isadvanced to the distal end of cartridge 22, at which time, all of thestaples once housed within cartridge 22 will have been ejected (see FIG.16). Thereafter, firing knob 50 is retracted to its original position,the cartridge and anvil sections are separated, and the spent disposableloading unit 20 is removed from retaining channel 14. Subsequently, anew, fully loaded disposable loading unit 20 can be positioned inretaining channel 14 such that the slot 40 of actuation sled 28 engagesflange or engagement member 42 of actuation channel 44 to enable re-useof the apparatus.

It is provided that the thermogenic energy applied to actuation channel44 also energizes the top surface of cartridge 22 and the thermogenicenergy applied to anvil support beam 80 or anvil half-section 11 benergizes anvil plate 90. Accordingly, the top surface of cartridge 22and anvil plate 90 behave in effect as two opposing electrodes forsealing tissue therebetween prior to being stapled and/or cut. Also, ifdisposable loading unit 20 has been spent, the apparatus 10 can just beused for sealing tissue by using the top surface of cartridge 22 andanvil plate 90 as the electrodes.

The thermogenic energy can be monopolar or bipolar radiofrequency, purethermal, and resistive heating, and is applied to the stapling apparatusto energize or heat the staples either directly and/or via one or moreconductive members before, during, and/or after the apparatus hasstapled, cauterized, and/or cut tissue. It is further provided to equipthe apparatus of the present invention with an impedance or otherfeedback mechanism for monitoring at least one characteristic, such asvoltage and current transients across the tissue, for improved tissuesealing.

Another preferred embodiment of the disclosure will now be describedwith reference to FIGS. 17-19. FIGS. 17 and 18 illustrate a fastenerapplying device shown generally as 200. Fastener applying device 200includes a housing 212 including stationary handle 214, a distallyextending body portion 216, and a transverse body portion 215.Transverse body portion 215 is configured to receive support frame 218.Housing 212 may be constructed from plastic material in the form ofmolded housing half-sections 212 a and 212 b. Housing half-sections 212a and 212 b are fastened together by a plurality of screws 219.Preferably, housing 212 is constructed from fiberglass reinforcedplastic, although other materials having the requisite strengthrequirements may be used.

FIG. 19 illustrates a perspective view of fastener applying device 200with the internal components of device 200 separated from each other.The device 200 may be is fastened together using screws 219 that extendbetween housing half-sections 212 a and 212 b, although adhesives,ultrasonic welding, and other known fastening methods may also be usedto fasten the components of the device together.

An anvil (not shown) is fastened to a first leg 224 of the support frame218. Any known fastening technique may be used to fasten the anvil tofirst leg 224. The support frame 218 is substantially U-shaped andincludes first leg 224, a second leg 226, and a base portion 228. Firstleg 224 extends substantially parallel to second leg 226. The supportframe 218 may be monolithically formed by bending a sheet of materialinto the desired shape. Preferably, support frame 218 is constructedfrom stainless steel, although other materials having the requisitestrength requirements may be used.

Cartridge carrier 238 is slidably supported about second leg 226 ofsupport frame 218 and is movable towards first leg 224. Cartridgeassembly 222 includes a body 204 having a distal face 206 which isspaced from an open proximal end 274. A pusher bar channel 208 extendsfrom the open end 274 through a portion of body 204. A plurality ofslots 210 house fasteners 221 (FIG. 19) and are configured to receivedistally extending fingers 276 of pusher bar 266. The slots 210 extendbetween the distal end of pusher bar channel 208 and the distal face 206of cartridge assembly 222. The outer surface of cartridge body 204includes a pair of transversely extending flanges 254. Cartridge carrier238 is provided with means for receiving and supporting cartridgeassembly 222.

The fastener applying device 200 has an approximation mechanism foradvancing cartridge assembly 222 and cartridge carrier 238. Anapproximating clamp 234 or lever is pivotably mounted about pivot member240 which is supported between housing half sections 212 a and 212 b inthe proximal end of housing 212. The approximating clamp 234 is movableinto engagement with a proximal end of clamp slide 236 to linearlyadvance the clamp slide 236 within body portion 216. A plurality oflongitudinal slots 242 formed in clamp slide 236 are configured toreceive guide pins 244 to limit clamp slide 236 to a linear path oftravel.

The distal end of clamp slide 236 includes a pair of projections 246.The projections 246 are fastened within a pair of openings 248 formed ina proximal end of cartridge carrier 238, such that linear movement ofclamp slide 236 is translated to corresponding linear movement ofcartridge carrier 238.

Referring to FIG. 19, approximating clamp 234 includes an abutment end262 having a series of detents which are configured to be received inrecesses 258 and 259 formed in an angled proximal end 260 of clamp slide236. The angled proximal end 260 of the clamp slide 236 and the abutmentend 262 of the approximating clamp 234 are movable into engagement toadvance the cartridge assembly 222 towards the anvil. Preferably,approximating clamp 234 is constructed of plastic and clamp slide 236,cartridge carrier 238 and pusher bar 266 are constructed of stainlesssteel. A proximal end of pusher bar 266 is connected to a wire 251 forenergizing pusher bar 266 and clamp slide 236 and in turn energizing thedistal end of pusher bar 266 which includes energizing distallyextending fingers 276. Wire 251 is preferably connected to anelectrosurgical generator for providing electrical energy to pusher bar266.

It is contemplated that wire 251 can be connected to any part of device200, such as first leg 224 and the metallic anvil, for energizing thefasteners via these members. For example, the anvil is energized whichin turn energizes the fasteners as they contact a surface of the anvilduring surgical stapling. It is preferred to coat the metallic anvilplate with an insulating material, such as Teflon, soft plastics (PVC),etc., to prevent the energized anvil from energizing tissue which iscontacted by the anvil.

During a surgical stapling procedure, as the fasteners are ejectedagainst a surface of the anvil, the fasteners scratch off the insulationcoating and make contact with the anvil, thus becoming energized. In thealternative, staple-forming cups or pockets of the anvil are not coated,such that the fasteners do not need to scratch off the insulationcoating. The rest of the anvil, however, is insulated.

FIG. 19 illustrates the firing mechanism for applying the fasteners ofdevice 200. The firing mechanism includes a trigger actuator 264 andelongate pusher bar 266 slidably received in a channel formed in clampslide 236. Trigger actuator 264 is pivotable about pivot pin 268 intoengagement with a proximal end of pusher bar 266 to advance pusher bar266 with respect to cartridge carrier 238. Pivot pin 268 is supportedbetween housing half-sections 212 a and 212 b.

The slots 242 of pusher bar 266 slidably receive the guide pins 244.Guide pins 244 limit pusher bar 266 to a linear path of travel identicalto that of clamp slide 236. The distal end of pusher bar 266 is formedwith a head portion 272 configured to move through the open proximal end274 of cartridge assembly 222 to effect ejection of fasteners 221. Theplurality of distally extending fingers 276 are integrally formed onhead portion 272. Each finger 276 has a concave distal surfaceconfigured to engage the fasteners 221 housed within cartridge assembly222 and energize the fasteners 221. Fingers 276 extend from head portion272 in a pattern that corresponds to the pattern that fasteners 221 arehoused within cartridge assembly 222. For example, the pattern may betwo staggered rows. Other patterns are also contemplated.

As illustrated in FIG. 19, the proximal end of pusher bar 266 has alocking surface 280 and a contact surface 282. The trigger actuator 264includes an engagement surface 284 which pivots into engagement withcontact surface 282 of the pusher bar 266 to advance the pusher bar 266distally.

When the pusher bar 266 is in a retracted position, locking surface 280of the pusher bar 266 is positioned to prevent engagement betweenengagement surface 284 of the trigger actuator 264 and contact surface282 of pusher bar 266. Thus, locking surface 280 prevents firingfasteners 221 prior to sufficient approximation of cartridge assembly222 and the anvil. Before trigger actuator 264 can be rotatedcounter-clockwise to eject fasteners 221 from device 200, theapproximating clamp 234 must be rotated clockwise toward the stationaryhandle 214 to advance clamp slide 236 distally. This frees triggeractuator 264 for pivotal movement to fire the fasteners 221.

An adjustment member 290 is provided in the distal end of the device 200to facilitate ejection of fasteners 221 from fastener applying device200. Adjustment member 290 includes a cylindrical shaft 292 having apair of diametrically opposed first and second flats 294 and 296,respectively. Cylindrical shaft 292 extends through an opening formed inthe second leg 226 of support member 218 and through the distal end of alongitudinal adjustment slot 298 formed in pusher bar 266. Theadjustment member 290 is secured to support member 218 by adjustment nut291. Shaft 292 is rotatable to align one of the opposed flats 294 or 296with a proximal end 299 of adjustment slot 298 to define a stop surfacefor the pusher bar 266. Since the flats 294 and 296 are formed atdifferent depths into the cylindrical shaft 292, shaft 292 may berotated to change the position of the stop surface to vary the stroke ofthe pusher bar 266.

An alignment mechanism is operatively connected to the approximationmechanism to maintain alignment between cartridge assembly 222 and theanvil during approximation of the anvil and cartridge 222. A moredetailed description of a similar fastener applying device as device 200is found in U.S. Pat. No. 5,964,394 having a common assignee as thepresent application. The entire contents of U.S. Pat. No. 5,964,394 areincorporated herein by reference.

With reference to FIGS. 20 and 21 there is shown another preferredembodiment of the disclosure having a monopolar arrangement as device200. FIGS. 20 and 21 illustrate a fastener applying device showngenerally as 300. Surgical stapling apparatus 300 includes a handleassembly 312 and an elongated body 314. A disposable loading unit or DLU316 is releasably secured to a distal end of elongated body 314. DLU 316includes a tool assembly 317 having a cartridge assembly 318 housing aplurality of metallic surgical staples and an anvil assembly 320 movablysecured in relation to cartridge assembly 318. Anvil assembly 320 ismetallic and is energized by a wire 321 connected thereto for energizingthe staples during a stapling operation. DLU 316 is configured to applylinear rows of staples. Wire 321 is preferably connected to anelectrosurgical generator for providing electrical energy to anvilassembly 320. It is contemplated that wire 321 can be connected to anypart of apparatus 300 besides anvil assembly 320.

It is preferred to coat metallic anvil assembly 320 with an insulatingmaterial, such as Teflon, soft plastics (PVC), etc., to prevent theenergized anvil assembly 320 from energizing tissue which is contactedby anvil assembly 320.

During a surgical stapling procedure, as the staples are ejected againsta staple-forming surface of anvil assembly 320, the staples scratch offthe insulation coating and make contact with anvil assembly 320, thusbecoming energized. In the alternative, staple-forming cups or pocketsof anvil assembly 320 are not coated, such that the staples do not needto scratch off the insulation coating. The rest of anvil assembly 320,however, is insulated.

Handle assembly 312 includes a stationary handle member 322, a movablehandle member 324, and a barrel portion 326. Handle assembly 312includes housing 336, which is preferably formed from molded housinghalf-sections 336 a and 336 b, which forms stationary handle member 322and barrel portion 326 of handle assembly 312. Movable handle member 324is pivotably supported between housing half-sections 336 a and 336 b.

A rotatable member 328 is preferably mounted on the forward end ofbarrel portion 326 to facilitate rotation of elongated body 314 withrespect to handle assembly 312. An articulation lever 330 is alsopreferably mounted on the forward end of barrel portion 326 adjacentrotatable knob 328 to facilitate articulation of tool assembly 317. Apair of retraction knobs 332 are movably positioned along barrel portion326 to return surgical stapling apparatus 300 to a retracted position asdescribed in U.S. Pat. No. 6,330,965 B1 having a common assignee as thepresent application. The entire contents of U.S. Pat. No. 6,330,965 B1are incorporated herein by reference.

Other types of staplers from those described herein can be designed toinclude energizing means for energizing the staples during a staplingprocedure, such as circular and endoscopic staplers.

Although the subject apparatus has been described with respect topreferred embodiments, it will be readily apparent to those havingordinary skill in the art to which it appertains that changes andmodifications may be made thereto without departing from the spirit orscope of the claims appended hereto.

1. A method for providing hemostasis along at least one staple lineduring surgical stapling, the method comprising: providing a surgicalstapler including: a loading unit that includes a cartridge having atissue contacting surface and a plurality of slots that house acorresponding number of surgical staples therein and a plurality ofstaple pushers configured to eject the staples from the slots when actedupon by a staple driving force; an actuator configured to translatethrough the cartridge in a longitudinal direction to transmit the stapledriving force to the pushers, the actuator coupled to a knife blade; andan anvil including an anvil plate having a staple forming surface coatedwith an electrically insulative material and energizable for energizingthe plurality of staples upon contact therewith when the anvil plate isin an energized state; disposing tissue between the anvil and thecartridge; ejecting the plurality of staples from the cartridge of theloading unit and driving the plurality of staples against the stapleforming surface of the anvil plate thereby removing a portion of theelectrically insulative material from the staple forming surface of theanvil plate to energize the plurality of staples and form a staple line;cutting the tissue with the knife blade; and then, heating the tissue bythe energized staples to improve hemostasis.
 2. A method according toclaim 1, further including the step of energizing the actuator.
 3. Amethod according to claim 1, wherein the step of providing includesproviding the knife blade that is electrically conductive.
 4. A methodaccording to claim 3, further including the step of energizing the knifeblade such that tissue is cauterized during an advancing step.
 5. Amethod according to claim 1, wherein the anvil plate is electricallyenergizable.
 6. A method according to claim 1, wherein the step ofheating includes providing thermogenic energy selected from the groupconsisting of radiofrequency, pure thermal heating and pure resistiveheating.
 7. A method according to claim 1, wherein the actuatorincludes: a base portion; a pair of upstanding cam wedges extending fromthe base portion for engaging the staple pushers during a firing of thestapler; and an upstanding shank extending from the base portion,wherein the knife blade is supported on the upstanding shank.
 8. Amethod for providing hemostasis along at least one staple line duringsurgical stapling, the method comprising: providing a surgical staplerincluding: a loading unit that includes a cartridge having a tissuecontacting surface and a plurality of slots that house a correspondingnumber of conductive surgical staples therein and a plurality of staplepushers configured to eject the staples from the slots when acted uponby a staple driving force; an actuator thermogenically energizable by agenerator and configured to translate through the cartridge in alongitudinal direction to transmit the staple driving force to thepushers while simultaneously energizing the pushers, the actuatorcoupled to a knife blade; and an anvil including an anvil plate having astaple forming surface that is coated with an electrically insulativematerial and thermogenically energizable by the generator for energizingthe plurality of staples upon contact therewith when the anvil plate isin an energized state; ejecting the plurality of staples from thecartridge of the loading unit and driving the plurality of staplesagainst the staple forming surface of the anvil plate thereby removing aportion of the electrically insulative material from the tissuecontacting surface of the anvil member to form a staple line; andsimultaneously energizing the plurality of surgical staples by way ofthe thermogenic energy delivered to the anvil plate and actuator whileadvancing the knife blade through the staple line such that tissue issimultaneously cut and cauterized; and heating the tissue by theenergized staples to improve hemostasis.
 9. A method according to claim8, wherein the step of providing includes providing the knife blade thatis conductive.
 10. A method according to claim 9, further including thestep of energizing the knife blade such that the knife blade cauterizestissue during the advancing step.
 11. A method according to claim 8,wherein the step of heating includes providing thermogenic energyselected from the group consisting of radiofrequency, pure thermalheating and pure resistive heating.
 12. A method according to claim 8,wherein the actuator includes: a base portion; a pair of upstanding camwedges extending from the base portion for engaging the staple pushersduring a firing of the stapler; and an upstanding shank extending fromthe base portion, wherein the knife blade is supported on the upstandingshank.